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Authorities are investigating the source of a noise that set off a chaotic night at LAX. Toni Guinyard reports for Today in LA on Monday Aug. 29, 2016. (Published Monday, Aug. 29, 2016)

Reports of a gunman opening fire that turned out to be false caused panicked passengers to stream onto the tarmac and street at Los Angeles International Airport on Sunday night, while flights to and from the airport saw major delays.

The central terminal area at LAX reopened around 11 p.m. Sunday, according to the LA Airport Police. Police had searched the airport after hearing reports of possible gunfire around 8:45 p.m. in Terminal 8. The reports were unconfirmed, the LA Airport Police posted on Twitter.

"Report of shooting at LAX proven to be loud noises only, no shots fired, no injuries. Investigation continues to locate source," LAPD's spokesman Andy Neiman posted on Twitter. The investigation included a review of closed-circuit video system footage.

Report of shooting at LAX proven to be LOUD NOISES only No Shots Fired No Injuries investigation continues to locate source

Investigators are still attempting to determine the source of the noises, police said early Monday.

Just before those reports, a person in a Zorro costume with what appeared to be a sword was briefly detained by airport police, authorities said. The sword was later determined to be plastic and the man was released, police said.

Police did not confirm whether the shooting reports and sword incident were related.

Lester Holt Describes Chaos at LA Airport

"NBC Nightly News" anchor Lester Holt had just arrived at LAX Sunday, Aug. 28, 2016, when passengers flooded out of a terminal after a report of an active shooter. The report turned out to be a false alarm.

(Published Monday, Aug. 29, 2016)

NBC Nightly News anchor Lester Holt was one of the passengers who had just arrived at LAX.

"We were about to walk upstairs when people began flooding out," Holt said. "Passengers, security people... I heard, 'shots fired' or 'active shooter,' 'run.'"

The security scare stirred "complete chaos," as one passenger put it. Hundreds of people rushed from terminals on to sidewalks or the tarmac. And it left a mess with three terminals shut down, roads closed and flights held in the air and on the ground.

The Federal Aviation Administration held LAX-bound flights at departure airports west of and including Minnesota, according to FAA spokesman Ian Gregor. The ground stop was later amended to include only flights departing from airports within about an hour's flying time of LAX.

During the 30-minute ground stop, 23 arriving flights were diverted to other airports, including 12 to Ontario. About 120 arriving and departure flights were delayed and six cancellations occurred during the reponse.

"We were on the jetway and someone starts pushing behind us," Jon Landis, a sales representative from Boston who was boarding a flight home, told The Associated Press. "One man was frantic saying there was a shooter."

Police officers, including one with a shotgun, eventually led passengers out of the terminal, through a security gate, and into a parking lot — where several hundred waited for the terminal to reopen. Ninety minutes after the scare, Landis said he was still waiting for word on his flight.

Douglas Lee, who was traveling home to Albuquerque with his wife and son, said the greatest danger was being trampled.

"You can imagine hundreds of adults trying to go through an exit door," he explained. At one point, he said he picked up his young son left their luggage.

Corey Rosenbusch was relaxing inside a terminal club on a layover flight from his home in Washington, D.C., to Sydney, Australia, when the lights went off and the staff told everyone to shelter in place.

"People immediately started looking at social media, where they saw reports that there was an active shooter," Rosenbusch told the AP.

He said several officers, including some with assault rifles, led the group out of the area.

'Loud Noises' Cause Panic at LAX

Reports of a shooting at LAX were proven to be "loud noises" only. Kate Larsen reports for the NBC4 News at 11 on Sunday, Aug. 28, 2016.

(Published Monday, Aug. 29, 2016)

The incident came just days after another false alarm led to a panicked evacuation of Kennedy Airport in New York. In that incident, police were investigating whether an overly boisterous celebration of the Olympics on Aug. 14 led to noises that were misinterpreted as gunfire, with the ensuing chain reaction turning into a panic as crowds ran to evacuate.

The Los Angeles airport had an actual shooting in November 2013, when a man opened fire in the terminal, killing a security agent and wounding three other people. In 2002, a gunman opened fire on travelers near the El Al Airlines ticket counter, killing one and injuring four others.

All terminals and roads into the airport had been reopened by 11 p.m. PDT, about two hours after the initial reports, officials said. But massive backup faced travelers in their cars and in security lines. Passengers who fled had to be rescreened through security.